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Search Results: 1 - 10 of 523409 matches for " Maria A.;Baura "
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Early colonization pattern of maize (Zea mays L. Poales, Poaceae) roots by Herbaspirillum seropedicae (Burkholderiales, Oxalobacteraceae)
Monteiro, Rose A.;Schmidt, Maria A.;Baura, Valter A. de;Balsanelli, Eduardo;Wassem, Roseli;Yates, Marshall G.;Randi, Marco A.F.;Pedrosa, Fábio O.;Souza, Emanuel M. de;
Genetics and Molecular Biology , 2008, DOI: 10.1590/S1415-47572008005000007
Abstract: the bacterium herbaspirillum seropedicae is an endophytic diazotroph found in several plants, including economically important poaceous species. however, the mechanisms involved in the interaction between h. seropedicae and these plants are not completely characterized. we investigated the attachment of herbaspirillum to maize roots and the invasion of the roots by this bacterium using h. seropedicae strain smr1 transformed with the suicide plasmid putkandsred, which carries a mini-tn5 transposon containing the gene for the discosoma red fluorescent protein (dsred) constitutively expressed together with the kanamycin resistance gene. integration of the mini-tn5 into the bacterial chromosome yielded the mutant h. seropedicae strain ram4 which was capable of expressing dsred and could be observed on and inside fresh maize root samples. confocal microscopy of maize roots inoculated with h. seropedicae three days after germination showed that h. seropedicae cell were attached to the root surface 30 min after inoculation, were visible in the internal tissues after twenty-four hours and in the endodermis, the central cylinder and xylem after three days.
The type III secretion system is necessary for the development of a pathogenic and endophytic interaction between Herbaspirillum rubrisubalbicans and Poaceae
Maria A Schmidt, Eduardo Balsanelli, Helisson Faoro, Leonardo M Cruz, Roseli Wassem, Valter A de Baura, Vinicius Weiss, Marshall G Yates, Humberto M F Madeira, Lilian Pereira-Ferrari, Maria H P Fungaro, Francine M de Paula, Luiz F P Pereira, Luiz G E Vieira, Fábio L Olivares, Fábio O Pedrosa, Emanuel M de Souza, Rose A Monteiro
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-98
Abstract: A 21?kb DNA region of the H. rubrisubalbicans genome contains a cluster of 26 hrp/hrc genes encoding for the type three secretion system (T3SS) proteins. To investigate the contribution of T3SS to the plant-bacterial interaction process we generated mutant strains of H. rubrisubalbicans M1 carrying a Tn5 insertion in both the hrcN and hrpE genes. H. rubrisulbalbicans hrpE and hrcN mutant strains of the T3SS system failed to cause the mottled stripe disease in the sugarcane susceptible variety B-4362. These mutant strains also did not produce lesions on Vigna unguiculata leaves. Oryza sativa and Zea mays colonization experiments showed that mutations in hrpE and hrcN genes reduced the capacity of H. rubrisulbalbicans to colonize these plants, suggesting that hrpE and hrcN genes are involved in the endophytic colonization.Our results indicate that the T3SS of H. rubrisubalbicans is necessary for the development of the mottled stripe disease and endophytic colonization of rice.
Evidence for the endophytic colonization of Phaseolus vulgaris(common bean) roots by the diazotroph Herbaspirillum seropedicae
Schmidt, M.A.;Souza, E.M.;Baura, V.;Wassem, R.;Yates, M.G.;Pedrosa, F.O.;Monteiro, R.A.;
Brazilian Journal of Medical and Biological Research , 2011, DOI: 10.1590/S0100-879X2011007500004
Abstract: herbaspirillum seropedicae is an endophytic diazotrophic bacterium, which associates with important agricultural plants. in the present study, we have investigated the attachment to and internal colonization of phaseolus vulgaris roots by the h. seropedicae wild-type strain smr1 and by a strain of h. seropedicae expressing a red fluorescent protein (dsred) to track the bacterium in the plant tissues. two-day-old p. vulgaris roots were incubated at 30°c for 15 min with 6 x 108 cfu/ml h. seropedicae smr1 or ram4. three days after inoculation, 4 x 104 cells of endophytic h. seropedicae smr1 were recovered per gram of fresh root, and 9 days after inoculation the number of endophytes increased to 4 x 106 cfu/g. the identity of the recovered bacteria was confirmed by amplification and sequencing of the 16srrna gene. furthermore, confocal microscopy of p. vulgaris roots inoculated with h. seropedicae ram4 showed that the bacterial cells were attached to the root surface 15 min after inoculation; fluorescent bacteria were visible in the internal tissues after 24 h and were found in the central cylinder after 72 h, showing that h. seropedicae ram4 is capable of colonizing the roots of the dicotyledon p. vulgaris. determination of dry weight of common bean inoculated with h. seropedicae smr1 suggested that this bacterium has a negative effect on the growth of p. vulgaris.
Genome of Herbaspirillum seropedicae Strain SmR1, a Specialized Diazotrophic Endophyte of Tropical Grasses
Fábio O. Pedrosa ,Rose Adele Monteiro,Roseli Wassem,Leonardo M. Cruz,Ricardo A. Ayub,Nelson B. Colauto,Maria Aparecida Fernandez,Maria Helena P. Fungaro,Edmundo C. Grisard,Mariangela Hungria,Humberto M. F. Madeira,Rubens O. Nodari,Clarice A. Osaku,Maria Luiza Petzl-Erler,Hernán Terenzi,Luiz G. E. Vieira,Maria Berenice R. Steffens,Vinicius A. Weiss,Luiz F. P. Pereira,Marina I. M. Almeida,Lysangela R. Alves,Anelis Marin,Luiza Maria Araujo,Eduardo Balsanelli,Valter A. Baura,Leda S. Chubatsu,Helisson Faoro,Augusto Favetti,Geraldo Friedermann,Chirlei Glienke,Susan Karp,Vanessa Kava-Cordeiro,Roberto T. Raittz,Humberto J. O. Ramos,Enilze Maria S. F. Ribeiro,Liu Un Rigo,Saul N. Rocha,Stefan Schwab,Anilda G. Silva,Eliel M. Souza,Michelle Z. Tadra-Sfeir,Rodrigo A. Torres,Audrei N. G. Dabul,Maria Albertina M. Soares,Luciano S. Gasques,Ciela C. T. Gimenes,Juliana S. Valle,Ricardo R. Ciferri,Luiz C. Correa,Norma K. Murace,Jo?o A. Pamphile,Eliana Valéria Patussi,Alberto J. Prioli,Sonia Maria A. Prioli,Carmem Lúcia M. S. C. Rocha,Olívia Márcia N. Arantes,Márcia Cristina Furlaneto,Leandro P. Godoy,Carlos E. C. Oliveira,Daniele Satori,Laurival A. Vilas-Boas,Maria Angélica E. Watanabe,Bibiana Paula Dambros,Miguel P. Guerra,Sandra Marisa Mathioni,Karine Louise Santos,Mario Steindel,Javier Vernal,Fernando G. Barcellos,Rubens J. Campo,Ligia Maria O. Chueire,Marisa Fabiana Nicolás,Lilian Pereira-Ferrari,José L. da Concei??o Silva,Nereida M. R. Gioppo,Vladimir P. Margarido
PLOS Genetics , 2011, DOI: 10.1371/journal.pgen.1002064
Abstract: The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme—GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species.
Diversity of 16S rRNA genes from bacteria of sugarcane rhizosphere soil
Pisa, G.;Magnani, G.S.;Weber, H.;Souza, E.M.;Faoro, H.;Monteiro, R.A.;Daros, E.;Baura, V.;Bespalhok, J.P.;Pedrosa, F.O.;Cruz, L.M.;
Brazilian Journal of Medical and Biological Research , 2011, DOI: 10.1590/S0100-879X2011007500148
Abstract: sugarcane is an important agricultural product of brazil, with a total production of more than 500 million tons. knowledge of the bacterial community associated with agricultural crops and the soil status is a decisive step towards understanding how microorganisms influence crop productivity. however, most studies aim to isolate endophytic or rhizosphere bacteria associated with the plant by culture-dependent approaches. culture-independent approaches allow a more comprehensive view of entire bacterial communities in the environment. in the present study, we have used this approach to assess the bacterial community in the rhizosphere soil of sugarcane at different times and under different nitrogen fertilization conditions. at the high taxonomic level, few differences between samples were observed, with the phylum proteobacteria (29.6%) predominating, followed by acidobacteria (23.4%), bacteroidetes (12.1%), firmicutes (10.2%), and actinobacteria (5.6%). the exception was the verrucomicrobia phylum whose prevalence in n-fertilized soils was approximately 0.7% and increased to 5.2% in the non-fertilized soil, suggesting that this group may be an indicator of nitrogen availability in soils. however, at low taxonomic levels a higher diversity was found associated with plants receiving nitrogen fertilizer. bacillus was the most predominant genus, accounting for 19.7% of all genera observed. classically reported nitrogen-fixing and/or plant growth-promoting bacterial genera, such as azospirillum, rhizobium, mesorhizobium, bradyrhizobium, and burkholderia were also found although at a lower prevalence.
Study of Thermodynamically Inspired Quantities for Both Thermal and External Colored Non-Gaussian Noises Driven Dynamical System
Monoj Kumar Sen,Alendu Baura,Bidhan Chandra Bag
International Journal of Stochastic Analysis , 2011, DOI: 10.1155/2011/721352
Abstract: We have studied dynamics of both internal and external noises-driven dynamical system in terms of information entropy at both nonstationary and stationary states. Here a unified description of entropy flux and entropy production is considered. Based on the Fokker-Planck description of stochastic processes and the entropy balance equation we have calculated time dependence of the information entropy production and entropy flux in presence and absence of nonequilibrium constraint (NEC). In the presence of NEC we have observed extremum behavior in the variation of entropy production as function of damping strength, noise correlation, and non-Gaussian parameter (which determine the deviation of external noise behavior from Gaussian characteristic), respectively. Thus the properties of noise process are important for entropy production. 1. Introduction In recent years the stochastic dynamics [1–5] community is becoming increasingly interested to study the role of noise in dissipative dynamical systems, because of its potential applications on various noise-induced phenomena, such as noise-induced phase transition [6], noise-sustained structures in convective instability [7], stochastic spatiotemporal intermittency [8], noise-modified bifurcation [9], noise-induced traveling waves [10], noise-induced ordering transition [11], noise-induced front propagation [12], stochastic resonance [13–15], coherence resonance [16–19], synchronization [20, 21], clustering [22], noise-induced pattern formation [23, 24]. In the traditional classical thermodynamics, the specific nature of the stochastic process is irrelevant but it may play an important role on the way to equilibration of a given nonequilibrium state of the noise-driven dynamical system. The relaxation behavior of the stochastic processes can be understood using information entropy ( ). Now the information entropy becomes a focal theme in the field of stochastic processes [25–28]. In [27] the authors have been studied the transition from the slow-wave sleep to the rapid-eye-movement sleep in terms of the information entropy. Crochik and Tomé [28] calculated the entropy production in the majority-vote model and showed that the entropy production exhibits a singularity at the critical point. The time evolution of mainly considers the signature of the rate of phase space expansion and contraction in the random force-driven Brownian motion. This implies that the specific nature of the random process has a strong role to play with . In view of the importance of the characteristics of the frictional and the random
Synchronization of Nonidentical Coupled Phase Oscillators in the Presence of Time Delay and Noise
Somrita Ray,Monoj Kumar Sen,Alendu Baura,Bidhan Chandra Bag
Journal of Complex Systems , 2013, DOI: 10.1155/2013/591513
Abstract: We have studied in this paper the dynamics of globally coupled phase oscillators having the Lorentzian frequency distribution with zero mean in the presence of both time delay and noise. Noise may be Gaussian or non-Gaussian in characteristics. In the limit of zero noise strength, we find that the critical coupling strength (CCS) increases linearly as a function of time delay. Thus the role of time delay in the dynamics for the deterministic system is qualitatively equivalent to the effect of frequency fluctuations of the phase oscillators by additive white noise in absence of time delay. But for the stochastic model, the critical coupling strength grows nonlinearly with the increase of the time delay. The linear dependence of the critical coupling strength on the noise intensity also changes to become nonlinear due to creation of additional phase difference among the oscillators by the time delay. We find that the creation of phase difference plays an important role in the dynamics of the system when the intrinsic correlation induced by the finite correlation time of the noise is small. We also find that the critical coupling is higher for the non-Gaussian noise compared to the Gaussian one due to higher effective noise strength. 1. Introduction In this paper we have investigated the synchronization behavior of globally coupled phase oscillators. Recent trends in physics [1–6] imply that it is one of the important issues in basic science such as the Brownian motion, nanomaterials, and biophysics. Biological clocks [7, 8], chemical oscillators [9–11], coupled map lattices [12, 13], and coupled random frequency oscillators [14] are examples where the phenomena of synchronization have been observed. To account the phenomenon, coupled phase oscillators model was introduced by Kuramoto [9–11], and it is popularly known as the Kuramoto model. After that, synchronization in nonlinear systems has been systematically studied and attracted much attention. Several reviews on the developments can be found in [1, 2, 5, 6]. Recently there has been considerable interest in some stochastic systems, whose dynamics are determined by both the present state and the state in the past with the time delay ( ). It has been considered in visual feedback [15, 16] and brain activity [17, 18] to mention a few. Delay is also studied in the coupled oscillator (CO) model [19–23]. In [19] authors showed that intrinsic frequency of the network of limit cycle oscillators decreases as the time delay grows, and for greater delay there is a metastable synchronized state. However, Nakamura
Assessment of Climate Change Impacts in Greece: A General Overview  [PDF]
Maria A. Mimikou, Evangelos A. Baltas
American Journal of Climate Change (AJCC) , 2013, DOI: 10.4236/ajcc.2013.21005
Abstract:

The climatic and hydrological systems are tightly related and any induced changes cause chained interactions. In an attempt to adequately manage water resources in Greece, a series of experiments were conducted with different GCMs in selected study areas to understand this interplay. This paper is an overview of the studies carried out in the Aliakmon, the Upper Acheloos, the Portaikos, and the Pinios basins, where the regional hydrological cycle was evaluated on river basin spatial scale to assess regional impacts and variability. The impacts of climate change on the water resources are presented in a synthetic quantitative way, in order to draw general conclusions concerning the trends of the hydrological indicators. A good agreement was observed between the different climatic experiments, and the trends on the selected hydrological indicators demonstrate an increase in temperature and PET, reduction in the mean annual precipitation and runoff, and a shifting of the snowmelt period towards the winter, while the snowpack storage was proved to be a controlling factor. It is accentuated that relatively small decreases in the mean annual precipitation cause dramatic increase of reservoir risk levels of annual firm water supply and energy production. As a result, radical increases of reservoir storage volume are required to maintain firm water and energy yields at tolerable risk levels. The adaptive capacity of the country is not that high, and a series of serious actions need to be taken in order to mitigate the effects of climate change and assess its impacts.

Differential Effects of Voluntary Ethanol Consumption on Dopamine Output in the Nucleus Accumbens Shell of Roman High- and Low-Avoidance Rats: A Behavioral and Brain Microdialysis Study  [PDF]
Maria G. Corda, Giovanna Piras, Maria A. Piludu, Osvaldo Giorgi
World Journal of Neuroscience (WJNS) , 2014, DOI: 10.4236/wjns.2014.43031
Abstract:

The Roman high(RHA) and low-Avoidance (RLA) rats were selectively bred for rapid vs poor acquisition of two-way active avoidance behavior. These lines differ in numerous behavioral traits, with RLA rats being more fearful/anxious than RHA rats, and the latter being novelty-seekers and showing larger intake of, and preference for, addictive substances including ethanol (ETH). Moreover, several differences in central dopaminergic, serotonergic, and GABAergic functions have been reported in these two lines. Since those neural systems are involved in the regulation of ETH consumption, it was considered of interest to investigate: 1) the differences in ETH intake and preference between RHA and RLA rats, 2) the effects of ETH on DA release in the shell of the nucleus accumbens (AcbSh) using brain microdialysis. ETH solutions of increasing concentrations (2% - 10%) were presented on alternate days in a free choice with water. To examine ETH intake and preference stability, animals were subsequently switched to daily presentations of 10% ETH for 10 consecutive days. RHA rats consumed significantly larger amounts of ETH and displayed higher ETH preference than did RLA rats throughout the acquisition and maintenance phases. Following chronic exposure to ETH the animals were habituated to a restricted access to ETH schedule (2% ETH, 2 h per day × 4 days) before surgical implantation of a dialysis probe in the AcbSh. Under these experimental conditions, voluntary ETH intake (2%, 1 h, p.o.) produced a significant increase in accumbal DA output in RHA rats but not in their RLA counterparts. Finally, the i.p. administration of ETH (0.25 g/kg) to na?ve Roman rats produced a significant increment in accumbal DA output only in RHA rats. These results indicate that the mesolimbic dopaminergic system of RHA rats is

Microfungal communities in soil polluted with fluoride  [PDF]
Galina A. Evdokimova, Maria V. Korneykova
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.29125
Abstract: There have been identified three zones according to the degree of soil pollution with fluoride in the impact area of air emissions of the Kandalaksha Aluminium Smelter (Russia): zone of maximum pollution up to 2.5 km from the emission source with the content of fluoride from 5000 to 1200 mg/kg, zone of strong pollution up to 13 km from the plant with the content of fluoride between 1200-400 mg/kg and zone of moderate pollution up to 20 km from the source with content of fluoride between 400-200 mg/kg. Emissions of the aluminium plant have reduced the number and the diversity of fungi and have caused an increase in fungal communities that are potentially pathogenic fungi. The biomass of fungi has decreased in the organic horizon of the maximum polluted soil from 5.4 to 3.6 mg/g. As a whole, emissions from the aluminium plant in the Murmansk region are less toxic for the environment, than emissions of copper-nickel enterprises.
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